The objective of the study was to investigate the seasonal variations in proximate and fatty acid composition of wild sobaity (Sparidentex hasta) for a one-year period during (i) pre-spawning (October–December), (ii) spawning (January–March), (iii) post-spawning (April–June) and summer (July–September). Five male and five female fish were collected from market each month and used for the study. Skinless fillets from both sides of sobaity were taken, chopped, minced, frozen and freeze dried. Freeze-dried ground male and female fish samples were pooled separately and homogenized for proximate composition and fatty acid analysis. The results of the investigation showed that the muscle proximate composition and fatty acid profile of sobaity differed significantly (P < 0.05) among different seasons with the highest muscle lipid during the pre-spawning and spawning season. Palmitic acid (C16:0) was the most dominant muscle fatty acid followed by oleic acid (C18:1n-9). The muscle docosahexaenoic acid (DHA, C22:6n-3) levels in pre-spawning and spawning seasons were significantly (P < 0.05) higher than those in other seasons. A good n-3/n-6 ratio (2.26–3.11) and the higher DHA levels (10.16–11.47%) observed in muscles during the pre-spawning and spawning season indicated a better nutritional value of sobaity at this time of the year.

As apex predators, sharks are known to play an important role in marine food webs. Detailed information on their diet and trophic level is however needed to make clear inferences about their role in the ecosystem. A total of 335 stomachs of smooth hammerhead sharks, Sphyrna zygaena, were obtained from commercial fishing vessels operating in the Ecuadorian Pacific between January and December 2004. A total of 53 prey items were found in the stomachs. According to the Index of Relative Importance (%IRI), cephalopods were the main prey (Dosidicus gigas, Sthenoteuthis oualaniensis, Ancistrocheirus lesueurii and Lolliguncula [Loliolopsis] diomedeae). Sphyrna zygaena was thus confirmed to be a teutophagous species. The estimated trophic level of S. zygaena was between 4.6 and 5.1 (mean ± SD: 4.7 ± 0.16; males: 4.7; females: 4.8). Levin's index (BA) was low (overall: 0.07; males: 0.08; females: 0.09), indicating a narrow trophic niche. We found that sharks <150 cm in total length consumed prey of coastal origin, whereas sharks ≥150 cm foraged in oceanic waters and near the continental shelf. The analyses indicate that S. zygaena is a specialized predator consuming mainly squids.

Snowpit samples collected at the West Antarctic Ice Sheet (WAIS) Divide location in January 2013 were analysed to investigate the levels and variations of perchlorate concentrations in Antarctic snow. During 2008–12, the perchlorate concentration in WAIS Divide snow ranged between 6–180 ng l–1 and followed a seasonal cycle. The highest concentrations appeared in the autumn, and the lowest in winter and spring. No apparent correlation was observed between perchlorate and nitrate or chloride concentrations in snow. Since perchlorate is believed to form in the atmosphere when chlorine species are oxidized in reactions involving ozone, perchlorate concentrations were hypothesized to be high during the spring, based on the assumption that stratospheric ozone depletion enhances tropospheric perchlorate production. The data show that perchlorate concentrations in snow were sharply reduced during stratospheric ozone depletion events; the evidence, therefore, does not support the hypothesis. Instead, the results suggest a stratospheric origin of perchlorate in Antarctic snow.

Food is an important factor for the survival of juvenile fish. Knowledge of the diet of co-existing species helps clarify their relationships with each other. A number of Mugilidae species are known to co-exist in estuarine systems, raising the question of whether they compete for food resources. The feeding behaviours of five juvenile Mugilidae species were studied in the estuaries of Strymonikos (North Aegean Sea) using stomach content analysis. It was found that the species Chelon labrosus, Liza saliens and Mugil cephalus presented high feeding activity during summer and autumn and L. ramada and L. aurata during winter and spring. The diet overlap between the species was generally moderate to low and the pair L. saliens – M. cephalus exhibited the highest overlap in Richios estuarine system. The species do not appear to compete for common resources, probably because there is not always a spatiotemporal overlap, enough food is available or they exploit different resources. Four out of the five species exhibited similar patterns of feeding strategies with varying levels of specialization at an individual level and a rather generalized pattern at the population level. This more generalized feeding strategy may permit them to co-exist. Only M. cephalus showed a more specialized feeding behaviour, with a strong preference for microalgae. The absence of a general pattern for the trophic levels according to seasons, sizes or locations, also imply the opportunistic character of the species. Both season and fish size influenced the variation in the diet composition.

We examined the spatial and temporal variations of coastal and oceanic epipelagic copepods (rainy–dry seasons of 2009) in a tropical area of the south-west Atlantic. Zooplankton samples were obtained at 48 stations along six transects perpendicular to the coast, in the subsurface water between the 25 and 3000 m isobaths, by horizontal hauls using a Multinet. Abundance (42–64,753 ind. m−3), biomass (0.08–113 mg C m−3) and daily copepod production (0.17–163.20 mg C m−3 d−1) showed longitudinal and latitudinal variability. The highest values were observed over the southern continental shelf during the dry season. Temoridae, Undinula vulgaris and Paracalanus quasimodo dominated the biomass and daily copepod production during the rainy season; while Calanoides carinatus, Calanopia americana, Clausocalanidae, Temoridae, Paracalanidae and Subeucalanidae dominated during the dry season. The copepod assemblages formed four different groups: rainy season–continental shelf (1), dry season–continental shelf (2), rainy season–continental slope (3) and dry season–continental slope (4). Temperature, salinity, chlorophyll-a and suspended particulate matter explained 45% of the productivity distribution of the dominant copepod species. This study is the first attempt to examine the biomass and daily copepod production in oceanic waters in the south-west Atlantic Ocean, and it showed that copepod biomass and production in a tropical region can be relatively high compared with other regions of the world's oceans.

Sea food is very rich in lipids. The brown shrimp, Crangon crangon is a most popular and very valuable taxon in the White Sea, in the Mediterranean and in the Black Seas. The aim of this study was to determine the seasonal variations of lipids in C. crangon muscle tissue using gas chromatography–mass spectrometry. The lipids were separated into groups: neutral lipids (triacylglycerols, free fatty acids, sterols) and polar lipids (phospholipids), by high performance liquid chromatography with a laser light-scattering detector. Fatty acids were identified using the GC-MS technique. The mainly fatty acids were 16:0, 18:0 (saturated FAs), 16:1, 18:1 (monounsaturated FAs), 20:4 (ARA), 20:5 (EPA) and 22:6 (DHA). The largest amounts of fatty acids in the muscle were observed in spring; these were the result of collecting food after winter and before reproduction. The muscle lipid content was 32.2 ± 1.8 mg g−1. The summer was the poorest season and the lipid value was 7.7 ±0.4 mg g−1. The levels of muscle neutral lipids (NL) oscillated between 80% (autumn) and 90% (spring). The temperature and salinity has a significant influence on content and profile of fatty acids. This work will help to understand the biology, the seasonal variation in lipid mass, lipid classes content and fatty acids profile in the abdominal muscle of C. crangon.

Field investigations on Perna perna were carried out in 1999 in an unpolluted site (Cap Ghir) and a wastewater-polluted site (Anza) to determine the contents of glycogen, lipids and proteins in mussel samples collected every month. Sample analyses were made using the entire soft masses of male and female mussels or their gonads only. Compared to unpolluted P. perna, the glycogen and lipid concentrations found in polluted mussels showed significantly quantitative variations throughout the year; in contrast, insignificant differences were only found for protein concentrations. Female gonads contained higher rates of lipids than male ones, whereas protein contents were similar. In contrast, in entire mussels, females were richer than males, whatever the biochemical parameter considered. Apart from protein rates in December, most of highest concentrations were noted from October to November. Contrary to unpolluted mussels (of which storage components were constituted by glycogen and lipids), a different reserve strategy, mainly based on the use of lipids, followed by that of proteins would exist in the P. perna from the polluted bed.

Maturity, mass and sex were determined for individual Raphidascaris acus from northern pike, Esox lucius from Dauphin Lake, Manitoba. Length, width and total fecundity of female worms; seasonal changes in worm numbers, growth and maturity; and inequalities in mass and fecundity were quantified for 8 sample periods between April and September. Recruitment of R. acus is most rapid in early spring and continues throughout summer. An accumulation of larvae over winter leads to a peak in the number of gravid worms in spring, while increased feeding by post-spawning pike on yellow perch, Perca fluviatilis, leads to lower levels of gravid worms throughout summer and early autumn. Gravid worms found in spring versus summer were similar with respect to all measured variables and do not appear to be from genetically distinct populations. The strength of the correlation between fecundity and mass for worms was variable between pike and between sample periods, and only weakly correlated when the data were pooled. Much of this variation could be attributed to continued growth of gravid worms after maturation. Worms found in June were smaller, less fecund and less variable and inequalities in mass and fecundity measured using Gini coefficients (GCs) and Lorenz curves (LCs) were most similar at this time. For all other sample periods inequality in fecundity was greater than the corresponding value for mass. Similarity between GCs based on mass and fecundity was maximum when the coefficient of variation (C.V.) for mass was greater than the corresponding C.V. for fecundity. These observations suggest that one must be cautious when applying GCs and LCs to the analysis of parasite populations.

The impact of alien American mink on the native fauna of oceanic islands has been demonstrated in a number of locations. In the sub-Antarctic Cape Horn Biosphere Reserve of southern Chile the species is currently expanding in an area where the native fauna evolved in the absence of terrestrial predators. To evaluate any emerging problems we therefore investigated seasonal variation in prey use by mink on Navarino Island within the Reserve. We identified undigested remains in 414 scats collected from the shores of 27 ponds over January–November 2006. Diet consisted mainly of mammals and birds. Mammals, including both native and exotic rodents, were the predominant prey in all seasons but birds were of equal importance during the summer (when birds breed and their abundance and diversity increases on the island). Exotic rodents were the only identifiable mammalian prey item during winter. Native wetland birds constituted a substantial proportion of mink diet, and greater than that reported in other areas. Many birds breeding on Navarino Island are ground-nesting, a strategy that evolved in the absence of native mammalian predators. Considering the international importance of this region, our results emphasize the need for an assessment of the impact of mink predation on the populations of native prey.

Sixteen coral sites in the coastal waters of Hong Kong were examined for the corallivorous muricid gastropods Drupella rugosa and Cronia margariticola. These were recorded from all sites where there was significant hard coral cover and observed feeding upon species of Platygyra, Leptastrea, Stylocoeniella, Porites, Favites, Cyphastrea, Goniastrea, Favia, Acropora, Montipora, Pavona, Lithophyllon, Hydnophora, Echinophyllia and Plesiastrea. One large aggregation (~2000 individuals) of, mainly, D. rugosa was observed but much smaller groups (<20 individuals) were more typical. Five sites were chosen for more detailed study and surveyed during winter and summer. Despite being characterized by different coral communities, inter-site densities of D. rugosa were not significantly different and, usually, ~2 individuals · m2 were recorded. Seasonal differences were, however, significant with numbers greater during the summer, possibly related to reproduction. Feeding activity followed a similar pattern and was also largely confined to summer.

Prey selection by Drupella rugosa was complex in the field and changed according to the relative abundance of each coral taxon. Acropora was strongly selected for at all sites where it was present and Montipora, Platygyra and Pavona were usually fed upon in greater proportions than their abundances. Leptastrea, Cyphastrea, Favites, Favia and Goniastrea were fed upon but in proportions lower than suggested by their abundances. Goniopora was never fed upon despite being relatively common. The seasonality of feeding, low density, rarity of large feeding aggregations, prey selection and aspects of the feeding behaviour, that is, generally only consuming the coral's coenenchyme (the polyps surviving), suggest that while D. rugosa is widespread in Hong Kong, and contrary to other views, it poses little, if any, threat to local coral communities. Thus, reported feeding clusters of D. rugosa are probably not ‘plague’ outbreaks but examples of seasonally fostered ‘aggregations’ of feeding (and probably reproducing) individuals. Indeed, no ‘plague-like’ outbreak of any species of Drupella has been reported upon in the literature since 1999.

In the Molise region (Italy), some autochthonous populations are still bred and, between them, some wild horses named ‘Pentro horses.’ The breeding area is a natural pasture. It is 2200 ha extended including a broad plane surrounded by wooden hills. The aim of this research was to determine the nutritional characteristics of this area over a 2-year period to improve the management of the herd and to define the stocking rate in relation to the forage production in terms of production and quality. The forage samples were collected over two successive years during the grazing period (May to October) from five experimental areas and analysed for dry matter (DM), organic matter (OM), crude protein (CP), crude fibre (CF), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), acid-detergent lignin (ADL) and gross energy (GE). Horse feed units (HFU) and horse-digestible crude protein (HDCP) were also predicted. Data were analysed with a one-way ANOVA test using month and area as factors. The DM, HFU and HDCP total production was determined to be compared with the total nutrient requirements of the herds from May to October. The results show that seasonal and yearly climatic variations significantly affect chemical composition and nutritive value of the pasture. The parameters most influenced were DM, CP, ADF and to a less extent NDF, while OM, ADL and GE show smaller differences during the observed period. The results show a low production per ha; nevertheless, because of the low stocking rate (0.3 to 0.6 head per ha), nutrient production meets the nutrient requirements of the horses regarding DM and energy. The differences among the areas have to be ascribed to the different botanical compositions and to the different draining capacity of the soil, and also in this case the greatest variations are for DM, CP and ADF.

During 2001 - 2002, we studied periphytic biomass at 5 sites along the Agüera stream (Northern Iberian Peninsula), and comparedthe results to those from two previous researches (1990 - 1991 and 1992 - 1993). Sampling sites showed large differencesin cover, conductivity and nutrient contents, as well as some inter-annual differences, resulting from changes in discharge andin human activities. Most environmental variables showed low seasonality, main variations being produced by floods. Solarradiation changed little during 2001 - 2002, because of the coincidence of a sunny winter followed by a cloudy summer, andseasonal differences in riparian cover resulted in more sunlight reaching the streambed of closed sites during winter, and smalldifferences at the open ones. The growth and abscission of riparian leaves results in a strong light regime at the closed sites, withmore sunlight during winter, but this pattern changes from year to year, depending on the weather. Spatial differences and highestvalues of periphytic biomass were much lower than those measured in 1990 - 91, because of contrasting weather patterns.Variables controlling periphytic biomass in the Agüera change from reach to reach. At open sites flow is the main temporalcontroller, whereas at closed sites the effects of light availability prevail, thus giving more similar seasonal patterns from yearto year. Nutrients seem to play a minor role in temporal variations.

Les variations verticales et saisonnières de l'activité de la phosphatase alcaline (APA) des communautés microplanctoniques ont été étudiées dans le lac réservoir mésotrophe Allai El Fassi, situé sur l'oued Sebou. Les échantillons ont été collectés à différentes profondeurs au point le plus profond du lac, de mars à décembre 1998. Les résultats montrent que l'APA totale est exclusivementassociée à la fraction de taille 0,22-100 μm dont les valeurs moyennes sont comprises entre 0,107 et 1,780 mmol PNP1-1 h-1 . La fraction dissoute (< 0,22 μm) ne présente aucune activité liée à cette enzyme. Au niveau des couches superficielles,plus de 60 % de l'APA totale sont corrélés à la fraction de taille 0,22-0,65 μm à majorité bactérienne. Cependant, avec la profondeur,l'APA est plutôt associée à la fraction de taille 0,65-100 μm à dominance phytoplanctonique (> 58 % de l'APA totale).Cette activité liée aux algues est significativement corrélée avec la densité phytoplanctonique et avec les concentrations de lachlorophylle a. L'absence de corrélation significative entre l'APA et les teneurs en phosphore total et orthophosphates suggèreune indépendance entre l'APA et les orthophosphates.

This study described the diet of the orange-rumped agouti Dasyprocta leporina in French Guiana. Five food types were identified in stomach contents: seeds, pulp, fibre, leaves and animal matter. D. leporina ate mainly fruit parts, pulp and seeds, although the ingestion of animals, leaves and fibre was not negligible. Food intake differed from one season to another. D. leporina was a pulp-eater (64.8% pulp in March) when fleshy fruit was plentiful and available on the ground (February–May). The level of pulp ingestion was globally in accordance with fruit production. When food resources were low (June–September), D. leporina consumed seeds and cotyledons (73.0% seeds in August) as well as animal (16.4% in July) and to a lesser level, plant parts. By focusing on other food categories, and particularly seeds, it gets nutritious food thus avoiding starvation between June–September. Large proportions of seeds appeared in stomach contents and correlations between seed quantities and ground production were negative and significant; D. leporina seemed to react to environmental factors such as rainfall and fruit production.

Animal burrows are major habitats for both P. martini and P. duboscqi, vectors of visceral and cutaneous leishmaniases in Kenya. In burrows, both species were collected throughout the year. The highest relative abundance of P. martini and P. duboscqi was recorded in August and in April, respectively. The lowest relative abundance was observed in july for P. martini and in October for P. duboscqi. In termite mounds, P. martini was present all the year round, but P. duboscqi was absent for the greater part of the year. The highest relative abundance of P. martini was observed in November and April, while that of P. duboscqi was seen in March and April. The lowest relative abundance of P. martini was recorded in July. In termite mounds, P. duboscqi showed a significant positive correlation with rainfall, contrary to P. martini which did not afford any significant correlation with any environmental factor. Rainfall, relative humidity and ambient temperature did not correlate with relative sandfly abundance in animal burrows.